<?php
/*
 *  $Id: Memcache.php 7490 2010-03-29 19:53:27Z jwage $
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

/**
 * Memcache cache driver
 *
 * @package     Doctrine
 * @subpackage  Cache
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link        www.doctrine-project.org
 * @since       1.0
 * @version     $Revision: 7490 $
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 * @author      Jonathan H. Wage <jonwage@gmail.com>
 */
class Doctrine_Cache_Memcache extends Doctrine_Cache_Driver
{
	/**
	 * @var Memcache $_memcache     memcache object
	 */
	protected $_memcache = null;

	/**
	 * constructor
	 *
	 * @param array $options        associative array of cache driver options
	 */
	public function __construct($options = array())
	{
		if ( ! extension_loaded('memcache')) {
			throw new Doctrine_Cache_Exception('In order to use Memcache driver, the memcache extension must be loaded.');
		}
		parent::__construct($options);

		if (isset($options['servers'])) {
			$value= $options['servers'];
			if (isset($value['host'])) {
				// in this case, $value seems to be a simple associative array (one server only)
				$value = array(0 => $value); // let's transform it into a classical array of associative arrays
			}
			$this->setOption('servers', $value);
		}

		$this->_memcache = new Memcache;

		foreach ($this->_options['servers'] as $server) {
			if ( ! array_key_exists('persistent', $server)) {
				$server['persistent'] = true;
			}
			if ( ! array_key_exists('port', $server)) {
				$server['port'] = 11211;
			}
			$this->_memcache->addServer($server['host'], $server['port'], $server['persistent']);
		}
	}

	/**
	 * Test if a cache record exists for the passed id
	 *
	 * @param string $id cache id
	 * @return mixed  Returns either the cached data or false
	 */
	protected function _doFetch($id, $testCacheValidity = true)
	{
		return $this->_memcache->get($id);
	}

	/**
	 * Test if a cache is available or not (for the given id)
	 *
	 * @param string $id cache id
	 * @return mixed false (a cache is not available) or "last modified" timestamp (int) of the available cache record
	 */
	protected function _doContains($id)
	{
		return (bool) $this->_memcache->get($id);
	}

	/**
	 * Save a cache record directly. This method is implemented by the cache
	 * drivers and used in Doctrine_Cache_Driver::save()
	 *
	 * @param string $id        cache id
	 * @param string $data      data to cache
	 * @param int $lifeTime     if != false, set a specific lifetime for this cache record (null => infinite lifeTime)
	 * @return boolean true if no problem
	 */
	protected function _doSave($id, $data, $lifeTime = false)
	{
		if ($this->_options['compression']) {
			$flag = MEMCACHE_COMPRESSED;
		} else {
			$flag = 0;
		}

		return $this->_memcache->set($id, $data, $flag, $lifeTime);
	}

	/**
	 * Remove a cache record directly. This method is implemented by the cache
	 * drivers and used in Doctrine_Cache_Driver::delete()
	 *
	 * @param string $id cache id
	 * @return boolean true if no problem
	 */
	protected function _doDelete($id)
	{
		return $this->_memcache->delete($id);
	}

	/**
	 * Fetch an array of all keys stored in cache
	 *
	 * @return array Returns the array of cache keys
	 */
	protected function _getCacheKeys()
	{
		$keys = array();
		$allSlabs = $this->_memcache->getExtendedStats('slabs');

		foreach ($allSlabs as $server => $slabs) {
			foreach (array_keys($slabs) as $slabId) {
				$dump = $this->_memcache->getExtendedStats('cachedump', (int) $slabId);
				foreach ($dump as $entries) {
					if ($entries) {
						$keys = array_merge($keys, array_keys($entries));
					}
				}
			}
		}
		return $keys;
	}
}